The purpose of this study is to compare the absolute levels (mg/dl) of plasma total cholesterol (TC) and lipoprotein cholesterol response of healthy subjects fed solid foods versus polymeric liquid defined formula diets of similar nutrient composition. Further, we will compare the relative magnitude of the plasma lipid and lipoprotein response between a cholesterol raising liquid defined formula diet and a cholesterol lowering liquid defined formula diet to the plasma lipid and lipoprotein response between a cholesterol raising solid food diet and a cholesterol lowering solid food diet. We hypothesize that there will be no signifigant difference in plasma lipid and lipoprotein response on individuals in solid food diets versus polymeric liquid defined formula diets that have the same macronutrient composition as the solid food diets, including fat, cholesterol and fiber composition. This study will determine whether the absolute or relative cholesterolemic results from liquid formula diets can be compared with those obtained with whole food diets. The establishment of equivalence would then provide investigators with the option to select either paradigm depending upon their specific needs. The practical implication of the present study will be to increase the ease of conducting controlled clinical trails to answer specific questions. If the cholesterolemic response on the liquid formula diets is similar to that observed with whole food diets, the use of liquid formula experimental diets will make diet planning simpler, reduce the nutrient variability associated with whole food diets and minimize costs (e.g. food production costs) of conducting clinical trials.